Are the datetime package and the memoir class known to conflict?

Question

Using the \formatdate macro from the datetime package within a \date definition seems to break when using the memoir class. Is this just something strange that I'm doing because it seems reasonable. A minimal example of this is:

\documentclass{memoir}
\usepackage{datetime}
\title{Dummy}
\date{\formatdate{1}{1}{2001}}
\begin{document}
\maketitle
\end{document}

causes pdflatex to complain saying:

Package fmtcount Warning: \ordinal already defined use \FCordinal instead. on input line 430.

(/usr/local/texlive/2012/texmf-dist/tex/latex/fmtcount/fc-english.def))))
! Incomplete \iffalse; all text was ignored after line 4.

I'm obviously doing something more complicated in reality and can work around this bug, but it's a bit unexpected!

Answer 1

You need to protect \formatdate:

\documentclass{memoir}
\usepackage{datetime}
\title{Dummy}
\date{\protect\formatdate{1}{1}{2001}}
\begin{document}
\maketitle
\end{document}